> where you can say bounce to sender Not sure what you mean. A bounce occurs when a receiving MTA refuses to accept delivery. The sending MTA might then compos

> where you can say bounce to sender Not sure what you mean. A bounce occurs when a receiving MTA refuses to accept delivery. The sending MTA might then compose a non-delivery message to the sender; but that's not under the receiving MTA's control. That is, if the sending MTA sends a "bounce message" direct to the sender's address, that's not specified by any email RFC, and is arguably bad behaviour - similar to running a "spam-bouncer" plugin on your email client, the bounces it issues are bogus. > all emails with a reply to of a certain msg id. I've no idea what that means. The reply-to is an email address, not a message-id.